KR101485655B1 - Process for production of coke - Google Patents

Abstract

The present invention relates to a method of manufacturing a coke capable of improving the strength of coke, and a method of manufacturing coke according to an embodiment of the present invention comprises: preparing at least one type of coke to form a coke; Preparing naphthalene tar from tar produced at the time of carbonization of coal to prepare dense naphthalene tar; Preparing a mixture by mixing the dense naphthalene tar on the compounded carbon; And drying the mixture to produce a coke.

Description

{PROCESS FOR PRODUCTION OF COKE}

The present invention relates to a coke making method, and more particularly, to a coke making method capable of improving the strength of coke.

Generally, the coke used in the blast furnace as a heat source, reducing agent, etc. as a means of ensuring air permeability is divided into a coke oven process, a coke oven process, and a chemical process. In the process of sintering, various kinds of coke are crushed and blended, And the coke oven process is a process of producing coke by flowing the compounded coal blended in the coal-fired process in a coke oven.

FIG. 1 is a schematic view showing a manufacturing process of a general coke.

As shown in FIG. 1, the coke scattered on the yard is crushed to have a predetermined particle size for each bullet type, and stored in each hopper for each bullet. On the other hand, in order to produce coke of a certain quality by using various types of coking coal, the mixing ratio of coal is calculated. Based on the calculated mixing ratio, the coal is removed from the corresponding hopper and discharged from the hopper, followed by mixing. The mixed blend can be selectively pretreated. For example, the blend can be dried depending on the presence or absence of coal drying equipment. Thereafter, the blended coal is supplied as a coal bin of a coke oven, and a certain amount of blast coal is discharged from the coal bin as a charging car and charged into the coke oven. Then, the blend charged into the coke oven is coked at high temperature for a certain period of time and then extruded from the coke oven, and the extruded coke is extinguished by wet or dry (nitrogen cooling).

 Coke oven gas (COG), tar and landscape oil are generated as a by-product during the process of manufacturing the coke. In particular, tar is a byproduct produced when carbon black is mixed with more than 90% of carbon, most of which is present as an aromatic compound. Tar improves the wettability of the cerium particles when mixed with cerium (compounding), and acts as a binder to contribute to the binding of the cerium particles by the chemical structure of the aromatic compound. In addition, tar is mixed with coking coal to improve the structural arrangement of the coke produced by retarding pyrolysis of the coke when it is dry, and to improve the charging density of the coke to be charged into the coke oven, thereby contributing to the improvement of coke quality.

In addition, tar produced as a by-product in the process of producing coke generates about 3% of the coke oven charged into the coke oven, and coke oven gas is used to purify tar, naphthalene and crude oil (benzene, xylene, toluene) And the purified coke oven gas is used as an energy source for other processes.

On the other hand, various types of coking coal are used to produce coke. Recently, the demand for coking coal has increased rapidly and the quality of coking coal has been limited due to the limited amount of good quality coking coal. Therefore, efforts are being made to develop and utilize various coal to replace high quality coking coal. In addition, the demand for high-quality coke is getting bigger due to the enlargement of the existing blast furnace due to the expansion of the content and the high-temperature blast furnace operation.

Therefore, various types of low-grade coal have been developed and used in order to solve the difficulty in supplying and discharging coking coal with good quality, but the use of such low-grade coal has been increased, And the quality of the coke produced by these problems deteriorates, making it difficult to increase the amount of low-grade coal.

Accordingly, there is an urgent need to develop a technique for manufacturing high-quality coke while using a large amount of low-grade coking coal.

Background Art [0002] In recent years, there has been proposed a drying technique for reducing the moisture content of coal charged in a coke oven to increase or decrease the quality of coke while increasing the use of low-grade coal, an oil adding technique for improving the charging density of coal charged in the coke oven, And a preheating technique in which the coal charged into the furnace is heated to 200 to 300 ° C to be charged, has been developed and applied.

In particular, recently, a technique for producing coke having a strength of a certain quality or more by mixing tar capable of serving as a binder in blending low-grade coking coal has been proposed and used. Techniques for producing coke by mixing tar with such blended coke are specifically known in "Coke production method and its manufacturing facility (Japanese Patent Laid-Open No. 10-2013-0006196;

However, the technique disclosed in Patent Document 1 is advantageous in that it can produce high-strength coke while using low-grade coking coal. However, it is a technique to mix tar generated in the process of coal coal blending with compounding coal, Since the tar (3% of the coking coal) generated and the tar (50% of the added tar) generated by the tar added to the binder are generated together with the coke oven gas, a large amount of harmful substances As shown in FIG.

As described above, the coke oven gas is used as an energy source for other processes after removing tar, naphthalene, and crude oil (benzene, xylene, toluene) through a separate purification process. Thus, When the substance is present, the coke oven gas is refined, but the refining of tar, naphthalene, sulfur and the like becomes insufficient. When the untreated coke oven gas is used as an energy source in the post-process, problems such as piping clogging due to the condensation of tar and naphthalene in the coke oven gas piping have caused various problems in the post-process.

Patent Document 10-2013-0006196 (Jan. 01, 2014)

The present invention provides a coke making method capable of producing a high-quality coke while using a large amount of low-grade coking coal.

Particularly, since the dense naphthalene tar which is a by-product of coal coal, tar, and naphthalene tar are added to the blended coal to produce coke, high-strength coke is produced and at the same time, a relatively clean by-product gas is generated, Thereby preventing clogging of the coke.

According to an aspect of the present invention, there is provided a coke producing method comprising: preparing at least one type of coking coal to form a coking coal; Preparing naphthalene tar from tar produced at the time of carbonization of coal to prepare dense naphthalene tar; Preparing a mixture by mixing the dense naphthalene tar on the compounded carbon; And drying the mixture to produce a coke.

The process of preparing the dense naphthalene tar may include collecting at least one of tar generated during the carbonization of the coal in the coke oven and tar generated in the refining process of the coke oven gas, and then distilling the collected tar to recover naphthalene Is separated.

The preparation of the dense naphthalene tar is characterized in that the collected tar is distilled while being heated to 250 ° C or higher.

And the tar collected in the process of preparing the dense naphthalene tar is distilled under an inert gas atmosphere.

The amount of the denatured tar tar in the mixture is 3 wt% or less (excluding 0 wt%) in the entire mixture.

It is preferable that the coking coal includes unbaked carbon.

According to the embodiment of the present invention, the naphthalene-tarned naphthalene tar was purified by purifying the tar generated in the coal coal process, and the naphthalene tar was added to the blend to produce the coke, thereby improving the cold strength and the hot strength while using a low- It is possible to produce high quality coke. Therefore, it can contribute to the reduction of coke manufacturing cost and the improvement of productivity.

In addition, since naphthalene-tar-free dennaphthalene tar is added and used, the coke oven gas generated in the process of compounding carbon can be cleanly generated, thereby improving the efficiency of the coke oven gas purification process, The problem of pipe closure caused by naphthalene or the like can be solved.

Fig. 1 is a view showing a manufacturing process of a general coke,
FIG. 2 is a view showing a manufacturing process of a coke according to an embodiment of the present invention,
FIG. 3 is a graph showing a change in weight due to an increase in temperature of tar and denaphthalene tar in a thermogravimetric analyzer,
FIG. 4 is a graph comparing changes in cold strength of coke due to the addition of tar and denatured tar,
5 is a graph comparing changes in hot strength of coke due to the addition of tar and denatured tar tar.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know. Wherein like reference numerals refer to like elements throughout.

FIG. 2 is a view showing a manufacturing process of a coke according to an embodiment of the present invention.

As shown in FIG. 2, the method of manufacturing coke according to an embodiment of the present invention includes: preparing at least one type of coking coal by mixing at least one type of coking coal; Preparing naphthalene tar from tar produced at the time of carbonization of coal to prepare dense naphthalene tar; Preparing a mixture by mixing the dense naphthalene tar on the compounded carbon; And drying the mixture to produce a coke.

The process of preparing the blended coal is the same as that of the conventional coke making process, in which the raw coal buried in the yard is crushed to a size of 10 mm or less for each type of coal, and the crushed coal has a particle size of less than 3 mm and a fraction of 80 to 90% And then stored in each hopper for each seed. In order to produce coke of a certain quality by using various types of cokes, the cokes are discharged from the corresponding hopper and discharged from the hopper on the basis of the coal type ratio calculated in consideration of the degree of coalification and the degree of cohesiveness of each coke. . The mixed blend can optionally be pretreated, such as a drying treatment. The coking coal used is a variety of coking coals ranging from high-quality coals to low-quality coals. Particularly, it is preferable that the present embodiment includes low-quality fine munitions of coking coal selected as a method for producing high-strength coke while using low-quality municipal coal.

The process of preparing the naphthalene tar is performed by collecting at least one of tar generated during the carbonization of the coal in the coke oven and tar generated in the refining process of the coke oven gas and then heating the collected tar in an inert gas atmosphere to distill This is a process for preparing naphthalene-free dennaphthalene tar.

The temperature at which the collected tar is heated should be at least the boiling point of naphthalene (217.97 ° C). It is preferable to distill and separate naphthalene in the collected tar by heating to 250 ° C or higher, and at the same time to distil off the low molecular harmful substances mixed in the collected tar. At this time, the naphthalene and the low-molecular-weight harmful substances are volatilized at different temperatures, and also serve to distill the mate- rials together.

On the other hand, the reason why the tar is heated in an inert gas atmosphere is that a low-molecular harmful substance mixed with tar collected during the heating of the collected tar is volatilized together with naphthalene. At this time, harmful substances combine with oxygen in the air, . In this embodiment, nitrogen may be used as the inert gas.

The dense naphthalene tar reinforces the cohesion of the blend which is mixed with various types of coking coal and improves the compactness of the coke structure in the process of coking the blend by softening, melting and solidifying in a high temperature coke oven. Particularly, the dense naphthalene tar which is a by-product of refining tar, which is a byproduct produced in the case of coal carbonization, is mostly composed of carbon. Most of these are present as aromatic compounds. When mixed with coking coal, the wettability between the coking coal particles is improved, As a binder.

When the blend and the denatured tar are prepared, the blend and the denatured tar are put into a mixer and mixed.

In preparing the mixture, the amount of the dennaphthalene tar added to the whole mixture is 3 wt% or less (excluding 0 wt%). The reason why the addition amount of the denatured naphthalene tar is limited to 3 wt% or less is that the cold strength and the hot strength of the produced coke are improved by mixing the dense naphthalene tar into the blend, but when it is added in an amount exceeding 3 wt% The improvement in strength and toughness strength is saturated and unnecessarily unnecessary addition of the dense naphthalene tar increases and the amount of tar present in the coke oven gas is increased to lower the refining efficiency of the coke oven gas .

When the mixture of the coal blend and the dennaphthalene tar is completed, the mixture is supplied to the coal bin of the coke oven, and a certain amount of the coal is discharged from the coal bin into the coke oven. Then, the blend charged into the coke oven is coked at high temperature for a certain period of time and then extruded from the coke oven, and the extruded coke is extinguished by wet or dry (nitrogen cooling).

[Example]

The following examples illustrate the present invention.

First, the weight change due to the increase in the temperature of the untreated tar generated in the conventional coal calcination process and the naphthalene-tar-free dense naphthalene tar used in the present invention were compared and the results are shown in FIG.

FIG. 3 is a graph showing a weight change due to an increase in temperature of tar and denaphthalene tar in a thermogravimetric analyzer. In the experiment, the temperature of the dense naphthalene tar and the tar of the comparative example were heated at 10 ° C / Weight loss was measured.

As can be seen from FIG. 3, the tar of the comparative example was slowly evaporated from 50 ° C by evaporation of moisture, and the pyrolysis started at 150 ° C., and the pyrolysis was completed at 573 ° C., Respectively.

On the other hand, dinnaphthalene tar, which is an embodiment of the present invention, begins to lose weight at a temperature higher than that of conventional tar, and is slowly pyrolyzed to 245 deg. C by thermal decomposition of a small amount of moisture and low molecular weight compounds, followed by rapid pyrolysis at 586 deg. The remaining char after pyrolysis was 25.5%.

From these results, it can be deduced that the naphthalene and the low molecular weight polymer material are thermally decomposed in the process of removing naphthalene from tar, so that the material remaining as char is more than that of the existing tar, It can be predicted that the addition of char material will increase the strength of the coke.

Next, in order to investigate the effect of the coke quality upon addition of the dense naphthalene tar to the blend, the tar and the naphthalene tar of the comparative example were added to the blend while changing the addition amounts, respectively, and then the cold strength and the hot strength were measured. Are shown in Fig. 4 and Fig.

FIG. 4 is a graph comparing changes in cold strength of coke due to addition of tar and denatured tar tar; FIG. 5 is a graph comparing changes in hot strength of coke with addition of tar and denatured tar.

The blends used in the experiments were prepared by mixing various types of coking coal. The results of industrial analysis, elemental analysis and cohesion analysis of the blends are shown in Table 1.

division
Industrial analysis Elemental analysis Calorific value Flow rate Total expansion ASH VM Fc TS C H N O Blend 9.52 26.23 64.25 0.56 87.87 5.45 1.41 4.71 7780 2.26 78

Here, ASH is the ash, VM (Volatile Matter) is the volatile content, FC (Fixed Carbon) is the fixed carbon, and TS is the abbreviation of Total Sulful.

The particle size of the blend was adjusted to be 86% or less at 3 mm or less. In addition, the naphthalene tar used as an additive in the blend was removed from the tar produced as a by - product in the production of coke.

The test was conducted by mixing tar (9.5% moisture) with tar (Comparative Example) and naphthalene tar (naphthalene tar) in an amount of 0, 1, 2, and 3% by weight and then mixing the tar and naphthalene tar The burrs were charged into a wood box at a loading density of 730 kg / m ³ on a dry base, charged into a coke test furnace heated to 700 ° C., and heated to 700 ° C. to 1100 ° C. at a heating wall temperature of 2.7 ° C./min , And after the oven center temperature reached 1000 ° C, the coke was extruded and dry-digested in a nitrogen atmosphere, and the cold and hot strengths of the thus-produced coke were measured.

Table 2 shows the flow rate and flow temperature range of the blend when 3 wt% of tar and naphthalene tar of the comparative example were respectively added to the blend.

division Maximum flow rate of Kisera meter
(ddpm) Flow temperature range
(° C) Tarry added 32 70 3 wt% of tar (comparative example) 49 82 3% by weight of dennaphthalene tar (Example) 109 103

As can be seen from Table 2, when the dense naphthalene tar (Example) is added to the blend, the flowability and the flow temperature range are significantly improved when the tar (comparative example) is added.

As can be seen from FIG. 4, the coke cold strength increased linearly with increasing the amount of dennaphthalene tar (Example), and the rate of increase in the strength of the coke decreased from 2 wt% or more. It is considered that the addition of dennaphthalene tar to the blend increases the flowability of the blend and increases the charging density. In addition, it can be seen that the effect of improving the flowability of the blended carbon when the dense naphthalene tar (Example) is added to the addition of the tar (comparative example) is greater and the coke cold strength is larger. On the other hand, when the addition amount of the denatured naphthalene tar exceeds 3 wt%, the degree of improvement of the cold strength is already saturated, and it is confirmed that the effect of adding the dennaphthalene tar is not large. Therefore, it is judged that the amount of the denatured tar added to the blend is 3 wt% or less, preferably 2 wt% or less.

Also, as can be seen from FIG. 5, the coke hot strength increased linearly with increasing amounts of dennaphthalene tar (examples). This is because the added dennaphthalene tar is pyrolyzed, discharged into gas and tar, and left in coke in the form of char so that the coke structure becomes dense, the porosity becomes low, and the CO ₂ reactivity decreases after coking, . Compared with the addition of tar (comparative example), the addition of dennaphthalene tar improves the density of the produced coke because the amount of char remaining after the denaturation of the naphthalene tar is higher than that of tar added It is considered that the hot strength was higher as the CO ₂ reactivity was lowered.

Based on the above results, it was confirmed that the tar and coke produced as byproducts in the coal blending were pretreated to increase the cold strength and hot strength of the coke produced by adding the naphthalene-free decal naphthalene tar.

In addition, since the use of dennaphthalene tar in which tar naphthalene has been removed in advance is used, it is possible to solve the problem that the purification efficiency of the coke oven gas is lowered due to the excessive mixing of naphthalene. In addition, the coke oven gas is used as an energy source It is possible to prevent the problem that the piping is closed by naphthalene in advance.

Although the present invention has been described with reference to the accompanying drawings and the preferred embodiments described above, the present invention is not limited thereto but is limited by the following claims. Accordingly, those skilled in the art will appreciate that various modifications and changes may be made thereto without departing from the spirit of the following claims.

Claims (6)

As a method for producing coke,
Preparing at least one type of coking coal by mixing the coking coal with at least one kind of coking coal;
Collecting the tar generated during the carbonization of the coal and distilling the collected tar while heating the collected tar at 250 ° C or higher to prepare naphthalene-tar-free denatured tar tar;
Preparing a mixture by mixing the dense naphthalene tar on the compounded carbon;
Lt; RTI ID = 0.0 > coke < / RTI >
The method according to claim 1,
The process of preparing the dense naphthalene tar may include collecting at least one of tar generated during the carbonization of the coal in the coke oven and tar generated in the refining process of the coke oven gas, and then distilling the collected tar to recover naphthalene Is separated.
delete The method according to claim 1 or 2,
And the tar collected in the process of preparing the dennaphthalene tar is distilled under an inert gas atmosphere.
The method according to claim 1,
Wherein the amount of the denatured tar tar in the mixture is 3 wt% or less (excluding 0 wt%) in the entire mixture.
The method according to claim 1,
Wherein the raw coke contains untreated carbon.

Images